Air tube and the like and method of reenforcing same



Aug. 11, 1931. M. s. HANNON 1,818,710 AIR TUBE AND THE LIKE AND METHOD OF REENFORQING' SAME Filed'Nov. 4-, 1927 2 Sheets-Sheet 1- l l l KE .AND METHOD OF REENFORCING SAME Aug. 11, 1931. M. s. HANNON' 1 AIR TUBE AND THE LI Fil d Nov. 4, 1921 2 Sheets-Sheet 2 Patented Aug. 11, 1931' UNITED STATES PATENT OFFICE MATTHEW STEPHEN HANNON, OF TORONTO, ONTARIO, CANADA, ASSIGNOR TO HANNON TIRE AND RUBBER COMP ANY LIMITED, OF TORONTO, CANADA AIR TUBE AND THE LIKE AND METHOD OF REENFORCING SAME Application filed November 4, 1927. Serial No. 231,144.

My invention relates to improvements in air tubes and the like and method of rein-V forcing same, and the objects of my invention are: first, to so reinforce or strengthenings forming part thereof, I shall describe,

and illustrate applications of the principle of my invention to externally and internally reinforce or strengthen air tubes, and a suitable type of machine to vulcanize the air tube, and what I claim as new will be set forth in the claims forming part of this specification.

In the preferred manner of putting my invention into practice, I utilize a wellknown form of tube vulcanizer, and wellknown means in forming a tube from a strip of suitable material before it is vulcanized, but it must be understood that the illustrations and description of said vulcanizer and said means, and the preferred manner of forming the air tube, are not "to beconstrued as limiting my claims in any manner whatsoever nor the applicationof the principle of my invention toair tubes and the like, no

matter how made.

Fig. 1 is a side elevation of a pulley or drum on which is formed theair tube prior to vulcanization thereof. Fig. 2 is a view of the reinforcing strip or tread before it is formed into a loop. Fig. 3 is a vertical central section through the inner or fixed member' of the ,vulcanizer before referred to; through the partly inflated air tube mounted thereon, and through the external reinforcing strip, showing how this latter depends below the partly inflated tube. One of the moi-able lower jaws of the vulcanizer is shown in open position. Fig. 4 is a view similar to ig. 3, except that the tube is fully Secondly, to

inflated and encased within the vulcanizer tu e. Fig. 5 is a view similar to Fig. 1,

showing the method of applying the internal reinforcing strip made of plastic non-curable material to the tube while being formed on the drum or pulley. Fig. 6 is a crossseotion through an inflated tube showing a suitable backing for the plastic non-curable material forming the internal reinforcing strip for the tube made after the manner of the tube illustrated in Fig. 5. Figs. 7 and 8 are side elevations of partially inflated air tubes, the one in Fig. 7 being formed by the extruding method, and the one illustrated in Fig. 8 being molded. In each case the reinforcing strip is shown as placed or hung over eachtube ready to be placed with the tube in the vulcanizing devices already shown, and Fig. 9 is a cross section, on an enlarged scale, the line 9-9, Fig. 7, omitting the air valve. In the drawings, like characters of reference refer to the same parts.

I shall describe the application of the principle of my invention to externally and internally reinforce the seam of air tubes made in the following manner. A strip of rubber or rubber compound of the desired size is placed on the drum or pulley 2, and in the usual manner the free ends thereof are overlapped or spliced. The required area of the exposed surface of the said strip is slightly dusted with powdered talc or equivalent material, and then one edge 3 is folded inwardly,

and the other edge 4 is also folded inwardly to well overlap the edge 3: these operations form the seam, and since there is no talc between the contactingsurfages of said edges, these remain stuck together. The valve stem (not shown in Fig. 1) is then placed in the tube in the usual manner. The formed air tube is now removed from the drum or pulley 2 and placed on a suitable circular support common in the art (not shown) to permit the tube to be partly inflated with air. The part-- 1y inflated air tube is now removed from said circular support and placed on the inner member 5 of the vulcanizer the surface of which has been dusted with powdered talc or its equivalent. The steps set forth are old and well-known in the art. The external reinforcing strip 6 is of the desired width and length, and the same is placed on the drum or pulley 2 and formed into a circle or loop with the ends spliced. After being formed the said reinforcing strip .is freely dusted on both sides with powdered talc or its equivalent, and it is then placed over the partly inflated and supported tube 7 below which it depends, as seen clearly in Fig. 3. The jaws 8 pivoted at 9, are now closed by means wellknown in the' art and not necessary to illustrate, thereby enclosing the air tube and the reinforcing strip 6 completely within the vulcanizer. Immediately said jaws are closed, the tube 7 is inflated by air to fully fill the cavity within the vulcanizer. This inflation of the tube will bring the same into contact with the whole of the inner surface of the strip 6, and since these contacting surfaces have been freely supplied with talc or its functionof retaining air willbe greatly imequivalent, air will be expressed from between the said tube and strip 6 before the process of curing is advanced, and consequently there is no possibility of air being imprisoned between the tube and the said strip to cause air pockets.

After suflicient time elapses to effect a proper cure, the air pressure within the air tube is reduced very materially and the jaws 8 are opened thus permitting the finished tube to be removed from the vuleanizer.

The size of the strip 6 is such as to form a loop which when vulcanized in place will not cause any circumferential contracting force on the tube with the result that the tube held within the'vulcanizer will expand uniformly throughout its parts with the result that the thickness of the walls thereof at each side of the reinforced seam will be substantially uniform and so make for the uniform durability of the same.

Since there are no air pockets, and since the walls of the air tubes are substantially of uniform thickness each side of the strengthening strip (3, it follows that by means of my method of manufacture I overcome any loss in manufacture through seconds or defective tubes. i

The principle of my invention can be ap-' plied tostrengthening or to reinforce inter..-' nally a seam-provided air tube so that its pro'vedespecially in case of a punctize;- In etube this case the strip of material to form f is placed on a drum or pulley 10, and the ends thereof overlapped 1n. the usual manner. Then the central portion of the outer surface of this material is coated with talc paste, and

then the strip 11 of plastic non-curablematerial is placed around the material out of which the tube is to be formed, as shown clearly in Fig. 5. Then the edges of the tube material are overlapped as shown at 12 and 13, thus forming the tube. The tube is of course provided with the air valve (not shown) as before-mentioned, in the usual way, and is then removed from the drum or pulley 10 and placed on a support to permit it to be partly inflated with air. The partly inflated tube is then placed on the inner member 5 of the vuleanizer, and the process of curing is carried out as before described.

Since the contacting surfaces of the strip 11 and the edges 12 and 13 are not coated with talc or its equivalent, they will stick together, thus holding the said strip 11 in place, and when the tube is inflated since talc paste has been located between the inner surface of the strip 11 and its associated tube, these parts will not adhere so that when the tube is fully inflated within the vulcan'izer the said strip 11 will maintain its position over the seam.

As before mentioned, the said strip 11 is made of plastic non-curable material such as plastic rubber, so that in case a nail should penetrate the tube and said strip 11, the hole will be automatically plugged sufficiently to prevent the rapid escape of air.

I sometimes find it advisable to place the plastic material 11 (see Fig. 6) on a thin strip of rubber 14: before placing the said material within the tube, so as to vpositively prevent the said material adhering to the tube while in the course of manufacture. Byusing the strip 14-, I can omit the use of the talc paste.

In Figs. 7 and 8 I show air tubes 15 and 16 which are made by the extruded and molded processes respectively. As shown in these figures, these tubes are partially inflated with air, and then the reinforcing or strengthening strips 6 are placed over them, and then each tube with its associated strip is placed in a suitable vulcanizer and the steps are carried out as already described to complete the union between the said-tubes and the respective reinforcing strips without causing any circumferential contracting forces circumferentially of said tubes.

If desired a strip or coating of plastic noncurable material 17 may be placed within the strip 6 shown in Figs. 7 and 9, so that in case of a puncture through said strip, the plastic material will plug the hole. As shown in Fig. 9, the ends 18 on the strips 6 extend well beyond the edges of the plastic material 17 so that these ends will be vulcanized to the tube and so positively hold the plastic material 17 in lace. j

. lthough I state-l prefer to dust the surfaces of the curable strip 6 for the purpose of suflicientl'y delaying curing so as to secure the removal of air between the strips 6 and its associated tube to prevent the formation of air pockets, I do not confine myself to using the powdered talc or its equivalent, because experiment may enable me to produce a rubber compound or its equivalent the curing of which will be sufficiently delayed to insure that all air be expressed between the strip and its associated tube.

In this specification and the claims forming part thereof, the term over is to be read as covering the strips 6 locatedoutside of the tube over the seam; or inside ofcthe tube against the seam.

10 While 1 have particularly stressed the application of my invention to the manufacture of air tubes for pneumatic tires, it must be understood that the principle thereof may also be employed in the manufacture of air bags used in certain types of vulcanizers, and

therefore my claims are to be read accordingly.

In Fig. 4, I have not cross hatched the air tube 7 nor the strengthening or reenforcing strip 6, as the construction is much more clearly seen as a consequence.

What I claim as my invention is: 1. The method of simultaneously sealing and externally reenforcing air tubes and the like at the seam, which consists in forming an air tube from a strip of suitable curable material with the seam at the'perimetcr thereof; then partly inflating the tube; then placing a loop of treated curable material of greater diameter than said partly inflated tube on said tube so as to depend therebelow, and then enclosing said tube and said reenforcing strip within a vulcanizing device and'immediately inflating said tube by air pressure to fit the w cavity of said vulcanizing device and bring the tube into contact with said loop of material.

2. The method of circumferentially reenforcing air tubes and the like, which consists in partially inflating an air tube; then placing a loop of treated curable material of greater diameter than said partly inflated tube, on said tube so as to depend therebelow, and then enclosing said tube and reenforcing strip within a vulcanizing device and immediately further inflating said tube to fit the cavity of said vulcanizing device and bring the tube into contact with said loop.

MATTHEW STEPHEN HANNON. 

